In article , IntarsiaCo
writes
There are numerous exceptions...

No, there is a continuum:

perennial herbshrubtree.

All possible intergradations occur.

There is no definite line where an herb becomes a shrub becomes a tree.


It's more unclear than you suggest - it's not a total ordering on a line
with unclear boundary points, but a more complicated topology. The
distinction between shrub and tree is made on several counts, which
means that there's several different ambiguous cases.

In the case of Lavatera arborea (Malva dendromorpha), is it a biennial,
a perennial, a subshrub, a shrub or a tree?

For a Victorian botanist's view on the general issue see

http://www.malvaceae.info/Literature...B/Chap1-1.html
(paragraph 13)
--
Stewart Robert Hinsley